Recent questions tagged C

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c - -O2 optimizes printf("%s ", str) to puts(str)

Toying around with clang, I compiled a C program containing this line: printf("%s ", argv[0]); When compiling ... ? How would I do that? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Why is "i" variable getting incremented twice in my program?

One of my friend showed me this program and asked me why is i variable getting incremented twice. According to ... incremented to 12 ? Thanks. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - different behaviour or sqrt when compiled with 64 or 32 bits

I'm using sqrt() function from math library, when I build for 64 bit using -m64 I'm getting correct result but ... for both x86 nad x64 cases. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Designated initializers and omitted elements

Can anybody please explain the following line about the designated initializers: The initializer list can omit elements ... only at the end. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Understanding memory allocation, test program crashing

I am just about finished reading K&R, and that is all the C that I know. All my compilation is done from ... ); } Followup question posted here. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Does stdlib's rand() always give the same sequence?

I quite like being able to generate the same set of pseudo-random data repeatedly, especially with tweaking ... the same seed obviously. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Char array subscript warning

when I use char array subscript as in this example: int main(){ char pos=0; int array[100]={}; for(pos ... on other signed types? Thank you. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Returning pointer to a local structure

Is it safe to return the pointer to a local struct in C? I mean is doing this struct myStruct* GetStruct() { ... return str; } safe? Thanks. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Kernel: how to iterate the children of the current process?

In Linux Kernel Development, 3rd ed, this code was given for traversing the children of the current process. ... . What is its purpose? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Malloc on linux without overcommitting

How can I allocate memory on Linux without overcommitting, so that malloc actually returns NULL if no memory is ... first write to the memory. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - fgetc(): Is it enough to just check EOF?

In various examples found on the web fgetc() is used like this: FILE *fp = fopen(PATH, "r"); if (fp == ... So need I check this too? And how? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - What is newline character -- ' '

This is a very basic concept, but something I have never been able to articulate that well. and I would like ... within vim?. Thanks, Jagrati See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - passing variable number of arguments

Can we pass variable number of arguments to a function in c? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - What's the equivalent of gcc's -mwindows option in cmake?

I'm following the tuto: http://zetcode.com/tutorials/gtktutorial/firstprograms/ It works but each time I double ... for -mwindows in cmake? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - What's the exact step of macro expanding?

This doesn't work as expected: #define stringify(x) #x printf("Error at line " stringify(__LINE__)); This works ... uses to expand such macros? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Unblock recvfrom when socket is closed

Let's say I start a thread to receive on a port. The socket call will block on recvfrom. Then, somehow in ... to use it for my specific case. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Iterating over all unsigned integers in a for loop

Let's say I want to iterate over all integers in a for loop. For the sake of discussion, assume I am ... too (iterate over all integers)? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Access violation writing location 0x00000000. reading int from keyboard

I am trying to read the input from a keyboard which i will use to create a set of multiplications. If ... trying to use an uninitialised value. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Check if a macro argument is a pointer or not

Is there some "nice" way to check if a variable passed to a macro is a pointer? e.g. #define IS_PTR(x) ... about this idea all the wrong way? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - What prevents the usage of a function argument as hidden pointer?

I try to understand the implication of System V AMD64 - ABI's calling convention and looking at the following ... %r12, %rax popq %r12 ret See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - FIFO pipe is always readable in select()

In C pseudo-code: while (1) { fifo = open("fifo", O_RDONLY | O_NONBLOCK); fd_set read; FD_SET(fifo, ... unreadable until it gets another write?) See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Problems casting NAN floats to int

Ignoring why I would want to do this, the 754 IEEE fp standard doesn't define the behavior for the following: ... output of the cast? Thanks! See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Is using strlen() in the loop condition slower than just checking for the null character?

I have read that use of strlen is more expensive than such testing like this: We have a string x 100 characters ... tempptr != ''; tempptr++) See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Issue implementing dynamic array of structures

I am having an issue creating a dynamic array of structures. I have seen and tried to implement a few examples on here ... part1[i]->index = x; See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Is strtok broken? Or just tricky?

Is strtok hopelessly broken? On many StackOverflow questions about text-parsing in C, someone will suggest using ... your answer with examples? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Input by using gets function

In Below Code When I want to Enter Record of second student or >2 student .. Compiler skip Name Input and take Input ... ].age); } getch(); } See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Slight Delay After Returning from Interrupt

I've written a small program that uses a button on an STM32 Discovery board to act as a counter in either Binary ... know why it is doing this. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - multiArray and multiArray[0] and &multiArray[0] same?

On 6th line instead of multiArray[0], when I write multiArray, program still works. Don't understand why. I was thinking ... +; } puts(" "); } See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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